The Ruin

An ancient ruin, a pair of boastful teenagers, and a bunch of indifferent gargoyles - but who let the demonic spirit out

This takes place one year after the events described in A Test of Loyalty. The GM should refer back to this module since many of the NPCs where first described therein.

This scenario can be run equally well as a sequel to those events or as a separate stand-alone module.

Introduction

It has been a year since Derry Althen joined the cult of the city guardian and she has made lots of new friends down the temple. The most notable of these is Orin van der Mewe, the son of the famous (some say infamous) mercenary, bounty hunter, adventurer and (if the rumours are to be believed) occasional bandit, Malinda van der Mewe.

Her father, Leonid Althen, has totally failed to notice the full significance of some of Derry’s new friends, as parents often do. Nonetheless he is a little worried about Orin, thinking that the boy might have "designs" on his daughter.

As it happens he really should worry about young Orin, but not for the reasons he suspects. The real problem is that Orin is that most dangerous of people: a natural orator with the ability to enthuse his audience. He is also something of a boaster.

Background - the Ruin

The Ruin is little more than an empty shell, its’ defences long since breached and its’ treasures all gone. It is said that from time to time the galleries hang with wonders, undefended and ripe for the plunder although there is little evidence to support such a claim. Nonetheless, stories of some lucky adventurer (normally "a friend of a friend") making his fortune from a single visit can be heard on any night in bars throughout the city.

Nobody knows for certain whether or not there is any truth to such tales, and nobody considers it worth the expense of mounting an expedition to the Ruin, but most travellers stop by whenever they are passing - just on the off chance. They never find anything of course; only empty galleries filled with broken pottery and spider webs (of the normal insect-eating variety).

The rich kids of the city

Over the years the Ruin has become something of rights-of-passage trip for the rich kids of the city. This normally involves going down there (usually when the kid is around 15 or 16 years of age) and wandering around for a couple of days (i.e. until he gets bored) looking for "The Lost Magic of the Ancients" (whatever that is). Some unfortunate servant often gets dragged along to act as a bodyguard, and some of the richer kids have even been known to hire mercenaries.

As expeditions go this is not particularly dangerous. The Ruin is only a few miles from the city (about a days’ travel time on foot, half that on horseback), mostly along a well travelled and (comparably) well patrolled road, and no dangerous creatures lurk within. The general view amongst the adventuring community is that this is all relatively harmless, if a little pointless, but does at least provide reasonably safe, and usually well paid, work for low level warriors (rich men will often pay top rates to indulge their offspring).

Denizens of the Ruin

Just because the Ruin is abandoned doesn’t mean that it’s uninhabited, far from it.

A small clan of gargoyles has taken up residence amongst the crumbling rooftops. Some claim that these are the remnants of ancient magical defences, but this seem unlikely since they largely ignore any "squishies" (such as human adventurers) who happen to wander around the place.

Since the gargoyles care little for human affairs they pose no real threat - unless, of course, somebody antagonises them.

Origins of the Ruin

The Ruin was built ages ago by a long dead civilisation as a kind of magical prison, not for men but for a powerful demonic entity known only as Deinos, the Fear-bringer.

Deinos had plagued the surrounding countryside for centuries, feeding off of the terror it inspired in men. Unable to destroy it, the shamans of old instead wove a web of the most potent confinement magics ever devised to imprison the demon for all time.

Stories of Deinos, first written down two centuries after it was imprisoned, have survived to this day but most scholars believe them to be purely fiction, a great read and all very exciting but with no basis in fact.

However, as with most powerful magic, the seals are not quite perfect. Deinos can extend a little of its’ power out into the catacombs. Not much, just a little, but it can take years for it to muster enough power even for this. But still it tries. Whenever there is somebody in the catacombs, and it has hoarded sufficient power, it tries to entice them to set it free.

Nobody has entered the catacombs for decades. So it waits. And it hoards its’ power. And it broods.

An expedition to the Ruin

The trouble really started about 25 years ago when Malinda van der Mewe was a young, and somewhat naive, wannabe adventurer trying to make a name for herself. Like most novice adventurers she was a sucker for maps to lost treasures, so when an unscrupulous trader offered her a map purporting to show the way to a powerful magical artefact, she bought it on the spot.

The map was actually a plan of the Ruin. After a short investigation revealed nothing of interest she packed it away and simply forgot about it. (Actually she always planned to avenge herself on the dishonest trader who sold it to her, but she never got around to it.)

A few years later when Malinda fell pregnant (rumoured to be the result of a brief, but passionate, liaison with a high ranking city official) she bought a house and settled down to a kind of semi-retirement. The map ended up in the attic along with several boxes full of accumulated junk.

There the map remained until Orin went rifling through the attic about a fortnight ago (as he often does) and chanced across it. Of course, he quickly realised what it was and an idea was born.

Orin’s boast

Orin has a much more accurate mental picture of the Ruin than most, but he’s not about to let that stop him trying to earn a little kudos from it. To that end he starts boasting to all his friends that he’s planning to go the Ruin, brave the angry spirits of the thousands tortured to death in its dark dungeons, and rediscover he lost magical arts of a bygone age. There is of course absolutely no truth in this, but it is a great story (especially the bit about the angry spirits), and everybody was very impressed.

Everybody, that is, except Derry Althen, who thinks she knows a bit about spirits. The resulting argument inevitably ended with Orin and Derry daring each other to mount an expedition.

And a day or so later Orin van der Mewe, equipped with a short sword "borrowed" from his mothers’ armoury, and Derry Althen, with a treatise on basic shamanism stuffed into her travelling pack, set out for the Ruin.

Derry Althen - human female, age 16 - ancestor worshipper, city guardian initiate - a lock of her mothers’ hair in a silver locket is a spirit totem for the ghost of Matty Althen - combat skill poor - minor magical ability (a few cantrips learnt from the family shaman)

Trapped in the catacombs

When Derry and Orin first arrived at the Ruin they did exactly what most teenage visitors do. First they wandered around the outer grounds for a bit but couldn’t find anything interesting. Then they picked a fight with a couple of gargoyles, the gargoyles responded by taking a few half-hearted swipes at them forcing them to take cover inside the main building. Finally they wandered around the hallways but found only cobwebs and shards of ancient pottery.

They were about to give the whole thing up as pointless when Orin, who has a little more knowledge of what to look for than most kids, spotted a concealed entrance opening onto a crumbling stairway down to the catacombs. Naturally they went down, thereby proving that they already possess the defining attribute of adventurers everywhere - a complete and total lack of common sense.

Once down in the catacombs they began to sense a ... presence. There was ... something down there with them. Something inhuman, something almost timeless, something that had waited for aeons. Something trapped. Something that desired, no needed, their aid.

It was Derry who guessed what it was, a spirit trapped on the mundane plane, unable to return to the Otherworld. To Derry (most of who’s relatives are spirits) this was wrong, it was sacrilege, it could not be. Her duty was clear - she must free this unfortunate spirit.

So she forged deeper into the catacombs searching for the focus of power, the one point at which she could have the greatest effect. She would not turn away, would not be stopped, and Orin had no option but to follow in her wake, despite his own misgivings.

When they finally reached the lowest chamber and found the heavy granite sarcophagus, Derry knew this was place. She didn’t know how she knew, but she knew it. Here was the focus, the centre of power. Here she could act.

Unable to break the ancient wards, Derry consulted her treatise on shamanism. After chalking out a Circle of Power on the stone floor she recited the Ritual of Calling the Spirit, in the hope that this would provide it with sufficient power to break free.

Her theory was sound but (perhaps luckily) she was unable to supply sufficient power, and the spirit remained trapped. However, the power boost had weakened the seals. The spirit could now extend its’ full power out into catacombs.

Only then did Derry realise the truth. This was no spirit; this was a demon - a malignant and powerful entity - a thing of nightmare that feeds upon the terror in men’s hearts. By then of course, it was far too late.

Where the PCs come in

Leonid Althen is getting extremely worried about his daughters’ disappearance. He contacted the Watch on the day she went missing. They interviewed all her friends and examined the records at the city gates and quickly learned that Derry and Orin had gone off to the Ruin. So they told him not to worry (teenage kids often do this but always return unharmed after a day or so), and to simply wait at home for her return. In the meanwhile they would place a watch on the city gates for her return.

That was over a week ago and there is still no sign. The Watch are not yet prepared to list her as a missing person. After all, an expedition to the Ruin could easily take a week or two (a day or two to get there, a few days wandering around the galleries, a day or two to get back).

On the other hand, they said, if Mr Althen would like to hire private help to retrieve his daughter, that is of course his right. And that’s where the PCs come in. If they have helped him before (e.g. in A Test of Loyalty) Leonid will again turn to them, if not the Watch could recommend them as competent investigators.

The Investigation

Working out where Derry has gone is easy enough. Leonid will tell the PCs the facts, as he knows them (i.e. what the Watch told him). The PCs are of course at liberty to talk to Derry’s friends, the Watch, the city gatekeepers, or anybody else they can think of.

Derry’s friends confirm that she and Orin were talking about mounting an expedition to the Ruin before they disappeared, although none of them know whether they actually did or not.

The gatekeepers will, if their tongues are loosened with a little silver, confirm that the pair left the city just over a week ago equipped for an extended camping trip and heading for the Ruin.

The Watch will reveal nothing unless the PCs can provide evidence that they are working for Leonid Althen, stating that it is a matter of confidentiality. Bribery will not convince them to talk (though they might take the money anyway). However, a signed letter from Leonid Althen to the effect that the PCs are investigating on his behalf will convince them to show the PCs their file. This reveals pretty much what the PCs already know, plus a formal Watch report to the effect that no laws have been broken and nothing either suspicious or worrying has occurred. It concludes that in the event of the pair not returning within one month they should be classed as missing persons, otherwise no official action is required.

The Ruin, Derry’s presumed destination, is of course well known to the adventuring community and the PCs can learn everything that is known about it (refer to Background - the Ruin; the Rich Kid of the City; and Denizens of Ruin) in almost any bar in town. In fact, if the PCs have been adventuring in the area for any length of time it is perfectly reasonable to assume that they already know most of this themselves.

The house of Malinda van der Mewe

The PCs will probably want the talk to Malinda van der Mewe. After all her son is missing too.

Her house is easy enough to find, being situated in one of the more fashionable areas of town (in fact not far from Leonid Althen’s house). However the only person currently there is Giletta, is an elderly slave woman who keeps house for Mistress van der Mewe. As long as the PCs are not unkind towards her, she will answer their questions honestly enough, although in truth she knows very little.

The Mistress left for the southern mountains about a month ago to hunt down a bandit gang that has been plaguing the trade routes of late (one of those nice fat government contracts that you need to right contacts to get). She is not expected back for two or three months.

Master Orin left about a week ago with a young girl about his own age and has not yet returned. Giletta thinks she is probably his girlfriend and they are currently shacked up at a wayside inn somewhere.

Giletta - human female, age 64 - slave (cook / housekeeper)

The house of Mistress Eskarina

If the PCs already knew Derry Althen before this (e.g. as her bodyguards in A Test of Loyalty) they might want to see if Mistress Eskarina, Derry’s great-grandmother, knows anything (after all the old woman is a shaman, and shamans have information sources beyond the ken of normal people).

As it happens Mistress Eskarina does know something but she is not at all sure what to do about it. She currently has a problem that is, although she is not aware of this yet, directly related to the PCs’ mission.

Four days ago the ghost of Derry’s mother, Matty Althen, appeared in her sitting room babbling incoherently about "nasty demons", "ancient ruins", "dark dungeons", and "poor little Derry". The poor spirit was clearly scared about something, and it obviously had something to do with her daughter, but without more detailed information the old shaman could offer no help.

Matty Althen - human ghost - panicked

Dealing with panicking ancestral spirits can be difficult, partially because the options are somewhat limited (the traditional slap on the cheek rarely works), but mainly because the dead do not perceive time in the same way as the living. From the human viewpoint a ghost might remain in a blind panic for centuries, or might recover so quickly that they seem entirely unaffected.

In this case it has taken Mistress Eskarina four days to get any kind of sense out of Matty. During this period the old woman has had very little sleep (a panicking ghost can be VERY distracting) so she is a bit crotchety at the moment.

When the PCs arrive, it is Cradoc (one of Eskarina’s sons and Derry’s great uncle) who answers the door. Cradoc acts as the old shamans’ secretary and liaison to the mundane world, which largely entails organising all the mundane necessities of life (like meals) that shamans, who spend much of their time in the spirit world, are apt to forget.

Cradoc - human male, age 67 - Eskarina’s secretary

Because the ghost of Matty Althen is currently occupying most of Eskarina’s efforts, Cradoc is currently under strict instructions not to disturb her unless it is strictly necessary. Consequently he will tell the PCs, politely but firmly, that mother is currently unavailable since she is attempting to resolve a family crisis involving his niece, which is of course basically correct. He does not bother to mention that his niece died 16 years ago, partially because he does not see this as significant, but mainly because he does not think it is any of their business.

However, if the PCs mention that they are looking for Derry he asks them to wait in the lobby and disappears through a side door. He returns a few minutes later and ushers them into the front room - Mistress Eskarina, it seems, is quite anxious to see them.

The scene that greets the PCs is, to say the least, a little strange. The old woman is sitting in a high-backed armchair with a cup of tea in her hand. Several elderly members of her clan are also present, at least half of who are spirits, all engaged in animated discussion. The centre of attention appears to be the ghost of a young woman (if the PCs have met the clan before they will probably recognise her as Matty Althen) who is flitting about the room in a most erratic fashion and babbling about her daughter. The general opinion of the room appears to be that the poor girl has completely lost her marbles and nobody seems to know what to do about it.

As the PCs enter, the room will grow extremely quite as everybody stops talking at once - everybody that is except the ghost of Matty Althen who is currently much too panicky to notice their presence.

The shaman’s aid

Mistress Eskarina will question the PCs closely regarding their mission, what (if anything) they already know or suspect, and their intentions when they find young Derry. If the PCs mention the Ruin, Matty gets very excited (even more so than she is already) and starts jabbering away so fast that it is impossible to follow what she is saying. Strangely the old woman seams to understand her (shamans, it would appear, can follow this high-speed spirit talk), and finally works out what is bothering the ghost - Derry has inadvertently awoken a demonic spirit and now she is trapped in the catacombs under the Ruin.

This, of course, comes as something of a surprise since nobody was aware that anything remotely dangerous lurked within the Ruin. However, Mistress Eskarina is unwilling to reject the word of an ancestral spirit (even one as young as Matty) out of hand and will want to investigate further. Consequently she will usher everybody out of the room so that she can commune with the Ancient Spirits.

If they so wish the PCs, now armed with the knowledge that they face a demonic spirit, are perfectly at liberty to leave. However Cradoc will suggest that they wait awhile since Eskarina may yet be able to aid them.

Mistress Eskarina spends most of the afternoon in the Otherworld, communing with the Ancient Ancestral Spirits. During this time her spirit is not resident within her body and she is therefore (technically at least) dead. Consequently everybody is extremely worried for the already frail old woman and nobody really takes much notice of the PCs, who will be left largely to their own devices. {{Note to GM: If the PCs can think of anything useful or helpful to do, let them do it - any such aid will be remembered, making it a lot easier for them to talk the old dear into providing magical aid in the future.}}

When she finally returns to the mundane plane, having spoken with the spirit of an ancestor who last walked the earth more than a millennia ago, Mistress Eskarina knows what the Ruin is - a magical prison, designed to hold a demon that inspires terror in the hearts of men. She also knows that Derry’s spirit has not yet travelled to the afterlife, and assumes therefore that the girl must still be alive (or she could be dead and her spirit trapped of course). She will give this information to the PCs.

If the PCs will swear an oath to rescue Derry or, if she is already dead, retrieve her body so that the proper ceremonies can be performed, Mistress Eskarina will give them a Charm of Courage to protect them from demons’ terror inducing powers. {{Note: This item is not required to complete the scenario but it will make the PCs’ lives a little easier.}}

Finally she will give them one last piece of advice - "remember the labyrinth". This she, explains, is a message for them from the Ancient Spirits but she is not sure what it means so the PCs will have to figure it out for themselves.

As for Mistress Eskarina; contacting spirits as ancient as this can be a draining process and the already frail old woman will never fully recover from her ordeal. Within a few days ill health will force her to retire to her bed, from which she will never again leave. Never again will she be able to perform so complex a ritual - she no longer has the strength for it. Quite simply, the old woman is dying, and she knows it.

Rescuing Derry

Sooner or later the PCs will have to conclude that Derry has indeed gone to the Ruin. If they have visited Mistress Eskarina they will be aware of the dangers involved, if not they may be inclined to simply leave her to it (after all, the place is perfectly safe). In either case Leonid Althen will insist that they go and retrieve her, if only to protect her from the advances of "that horrible little thug" (he’s beginning to take a distinct dislike for Orin van der Mewe).

When the PCs enter the Ruin they get a strange feeling that all is not well, that something is somehow ... wrong - it’s nothing tangible, nothing real, nothing they can really put their finger on - just an overpowering sense of ... disquiet.

Even in the outer grounds they will get the distinct impression that something is watching them, though what that something is they will have no idea. Once they get inside the Ruin proper, their fears develop an almost claustrophobic quality - as if the walls themselves are literally pressing in.

And just to make matters worse the gargoyles (who have been feeling a little on edge of late) are somewhat intolerant at the moment. It’s not that they will actively attack anybody, because they won’t, but they will react to any disturbance in a much more aggressive manner than is usual. So if the PCs antagonise them, even inadvertently, there is going to be a fight.

{{Note: Since Deinos is still restricted to the catacombs it cannot actually sense the PCs at this point, nor can it interact with them in any way. Therefore any misgivings they may have are entirely the products of their own imaginations.}}

A thorough search of this level will produce a few minor treasures, although some may not at first sight appear to be such. Some examples are listed here - feel free to add more in a similar vein:

(i) A four inch tall earthenware statue of a nude woman with exaggerated breasts and buttocks, stained a dull ochre red (similar to the Venus figurines of prehistoric Earth). This is identical to the figurine owned by Leonid Althen (refer to A Test of Loyalty) except that this one is intact. It is not magical in any way, nor is it particularly attractive. It is however a prime example of the (possibly religious) art produced by the Old Empire, which dominated this region over three millennia ago. It has no real value on the open market but certain specialist collectors (like Leonid Althen) would pay a tidy sum for it - you just have to know who to offer it to.

(ii) A small dull brown earthenware amphora about six inches tall with some form of runic script inscribed around the rim. Any archaeologist or ancient historian can immediately identify this as a common utility item from the days of the Old Empire, typically used to store scented bath oils. They almost always had an earthenware stopper, which this one has lost. Apart from the runic script around the rim, this is identical to examples found in several Old Empire sites. It has no significant monetary value. However it does detect as magical.

The amphora is in fact a spirit bottle, a magical item used in the Old Empire for entrapping certain types of minor spirit (in this case a healing spirit). However it is currently not operable because there is no stopper. If the PCs can work out what it is (Mistress Eskarina will be able to identify it for them) and locate a genuine spirit bottle stopper (remember Iza from A Test of Loyalty), they will have a usable magical item. Of course they will still need the spells to summon the relevant spirit.

(iii) A brass buckle bearing the emblem of the House of Maris, a wealthy trading clan from the city, lost by Alan Maris, the heir to the Maris fortune, when he was exploring the Ruin ten years ago. The buckle is a minor magical item and easily recognisable as such, however it is conditioned such that only a member of the Maris clan may see, and therefore use, its’ enchantment. This is of course of little use to the PCs, however if they return it to the Maris clan they can expect a small reward and, perhaps more importantly, a wealthy contact.

Eventually the PCs should find the concealed entrance to the catacombs. This should not be too difficult, partially because it is not particularly well hidden, but mainly because Derry and Orin have already uncovered it. {{Note to GM: If you have played the rest of the scene right, your players should be decidedly nervous about going down here.}}

Into the catacombs

As soon as the PCs descend into the catacombs, Deinos will become aware of them. From this point on Deinos will do all it can to terrify the PCs so that it can feed off of the psychic energy this produces, and thereby gain sufficient power to break completely free of its’ bonds. To this end it uses its’ powers of illusion to confuse and scare the PCs, backing this up with occasional telepathic messages regarding the futility of their position.

From the PCs’ viewpoint it will appear that the universe itself has turned against them: walls, doors, corridors, and rooms will appear and disappear apparently at random; great chasms will open up directly in front of or just behind the party; monsters will appear to teleport in and attack; etc.

Eventually the PCs should find Derry and Orin. However, the two kids have been trapped down here for several days and they are now half mad with terror (remember they have had more than a week of the terrors the PCs are experiencing). For all they know (and this will seem to them most likely) the PCs may just be another bunch of assassins come to murder them. The PCs will need to be very careful here or the kids may simply attack them. {{Note to GM: Orin will be by far the most paranoid. Derry, with her shamanic background, has guessed something of Deinos’ nature and has therefore managed to hold onto her sanity for a little longer. This is the PCs "in", if they can convince her they are real she will join forces with them. Orin will follow suit since Derry is about the only thing he really trusts at this moment.}}

Note that at no time does Deinos attempt the kill its’ captives (corpses do not have powerful emotions). The real danger here is that the PCs become hopelessly lost in the ever changing illusionary labyrinth, where their mounting paranoia serves to feed the demon for several days, or even weeks (i.e. until their supplies run out and they simply starve to death). Unless they have thought of some method of marking their true path (such as trailing a ball of string behind them themselves) they are likely doomed. {{Note to GM: You should allow any reasonably intelligent escape plan to work.}}

The continuing threat

Although it has been released from the sarcophagus, Deinos is by no means free. The magical seals are still partially intact and Deinos is therefore still trapped within the catacombs. In order to break these bonds Deinos must hoard a LOT more power, and that means it needs a lot of people to terrorise. Thus the demon is no significant threat to the surrounding countryside, as long as people stay out of the catacombs.

The obvious solution (at least in the short term) is to publicise the fact that an extremely dangerous demonic spirit now lurks within the catacombs, warning all potential visitors to steer clear. It will also be necessary to emphasise that the spirit guards no treasure, or it is not going be long before the usual assortment of would be looters (sorry heroes) start wandering all over the place.

Although this will likely deter most the of the teenage "rights of passage" expeditions (at least after two of three of them fail to return), it may well encourage more experienced parties to try and destroy Deinos. This, unfortunately, is impossible (which is, after all, the reason the Old Empire priests entombed it) but that will not prevent the attempts (PCs may get involved with such attempt if they so wish, but should learn only that such missions are doomed to failure).

Obviously a better long-term solution must be found, and the only one that presents itself is to repair and reinforce the magical prison. This is certainly possible (the Old Empire priests managed it) but would require complex and powerful magics currently well beyond the PCs abilities. {{Note to GM: This can, if you wish, become the basis for a campaign arc.}}

Wrapping Up

Although there are few material gains here (apart from the whatever fee the PCs managed to extract from Leonid Althen), some very important people are likely to owe the PCs a very big favour - once the full story comes out. That is, as long as they manage to rescue Derry and Orin (a difficult but be no means impossible task).

Leonid Althen is something of a rising star within the city’s ruling circles. If he didn’t know the PCs before he certainly does now and, regardless of that, owes them considerably more than mere money. He is not a rich man but, from the PCs point of view, a friend in government circles is always worth having.

Malinda van der Mewe likewise owes the PCs a really big favour, and having the city’s most famous and (at least by her reckoning) most dangerous adventurer on your side never hurt anybody.

Despite their experiences, both of the kids have discovered in themselves a taste for the adventuring life. Orin turns out to be a pretty good fighter (not perhaps very surprising considering his background) - one day, and not too soon at that, his mum is going to be really proud of him. Meanwhile Derry has clearly demonstrated a natural aptitude for magic (after all, she operated the Ritual of Calling the Spirit adequately enough) and Mistress Eskarina starts training her for shamanhood, much to her father's chagrin (nice young girls just don’t do that sort of thing). The PCs can expect to here a lot more about these two in the future.

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Backstory is good, but... this lengthy elaboration sits over a plot that consists of:
- Two kids get trapped in an illusory maze by a demon that feeds off their terror and confusion;
- A ghost and a shaman provide the PC's enough info and (optionally) minor magic to get them to the kids, and now the PC's are caught in the illusory maze;
- The PC's can use "any reasonably intelligent escape plan" to get out, but destroying the demon "is impossible" (by fiat).

Problems:
- Most of the color detail is irrelevant, and I'm not even sure how the PC's would learn it: There are some great roll-playing opportunities here, but they don't repay the time and effort with a correspondingly rich set of PC options;
- If played fairly, Orin is almost certainly going to end up dead, and I wouldn't give good odds on Derry;
- After all the front-side detail, the demon itself is shallow/hollow/devoid of any character at all!?! It has a tiny repertoire of actions (vaguely disquieting presence, confusing but fairly harmless illusions, modest suggestions), and absolutely no arc. This empty presence annoys the PC's for a while, then they leave. Fini.
- Most players are going to be severely frustrated, and likely spend much time fruitlessly searching for the "missing link" that allows some better resolution - and find the ending terribly anti-climatic.

But the voting clearly says I'm the one who is off-base, c'est la vie...

OK esaquam, not entirely unfair, but it think it largely depends how you (as GM) play it, and on what your players expect from a scenario.
So, let's deal with your queries in order:

Background
You're right, there is a lot of room for role-playing here, and this is largely how the PCs will get to learn it (or at least most of it). Also, if the PCs have played the previous scenario (refer to A Test of Loyalty) they will already know some of the background material regarding Derry and her clan.
As for the relevance of all this detail - well that largely depends on how you use Deinos in the future (more on that later).

The Kids
Orin and Derry are in deep trouble, but the CAN be rescued - it's just not going to be easy. And if the PCs get this wrong (which is all too easy to do), they are quite likely to end up dead.

The Demon
Deimos is, as you suggest, a little shallow at present. This is largely because I has been trapped in the sarcophagus for centuries, perhaps even millennia (depending on when you place the demise of the Old Empire in your universe), and it therefore has few desires at the moment beyond escape.
This is also the reason its' powers are currently so limited. It has had very little to feed upon during its' imprisonment (few people venture down into the catacombs) and the lack of substance has weakened it - quite frankly its' starving.
Once it gets out, which is not an immediate threat but might certainly by possible in the longer term, it could well become a lot more sophisticated. How it develops is largely up to you (at least for the time being).
The trick here, as GM, is to use this as a kind of set-up scenario to present the problem (you know the sort of thing - the demon is coming but it can be stopped, but only if you act BEFORE it gets too powerful)

The Players
Whether or not your players get frustrated by all this is largely dependent on what they expect from the game.
Hack-n-slayers are certainly not going to like this (way too much thinking and no where near enough magical goodies and to cap it all they don't get to ill to kill the monster).
Role-players, on the other hand, could get seriously engrossed in long-term plot - as long as you present it correctly.

But they are gone. Today, I would suggest to cut this up into scroll posts, and happily interlink with itself and the other adventures. It is an okay submission, with the others of this series it rises in quality, making a full campaign with heaps of details and opportunities of side adventure. Verbose, too. :)

Link Backs

The Iron Ship

Perhaps the product of another universe or time, this vessel appears as an early Tall ship, but is made of iron from keel to spar. The sails are a battered canvas but are nearly indestructible, but in truth do little to move the ship - the ship is able to move even with no winds.
The ship is powered by life force, requiring regular sacrifices to ‘charge’. The victims are cast in front of the vessel as it moves, it’s razor sharp bow bisecting them. The ship may initially be missing key components and the ritual to power it would also require research by would-be users.
The ship has no built in weapons aside from the bow, which can easily cut even large wooden ships in twain.